A storage apparatus mounted with a plurality of storage units has been widely distributed. Such a storage apparatus is, for example, referred to as a disk array device. In many cases, a plurality of hard disk drive units (hereinafter, referred to as “HDD units”) are mounted in the disk array device.
Related techniques are disclosed in, for example, Japanese Laid-Open Patent Publication No. 2005-149684, and Japanese Laid-Open Patent Publication No. 2014-086123.